1. Field of the Invention
This invention relates to adhesive labels and their use on containers. More particularly, it concerns improvements in adhesive blind labels, that is, labels which contain information which is covered up or "blinded" so that the users or some portion of the users cannot have access to it.
2. General Background and Prior Art
Usually, labels are provided to convey information. At times, however, it is essential that labeling materials be capable of carrying information but withholding some of it from direct access by casual examination. A good example of this arises during comparative tests of drugs and other products where it is essential to impartiality and to reliable test results that the parties directly involved in the test procedure not know whether or not they are actually testing the new material. Such tests are often referred to as "blind" tests or, in the preferred case where both the test subject and the person administering the test are kept in the dark, "double-blind" tests.
Conventionally, blind labeling of products has been carried out on an individual basis with the labeler attempting to conceal the blind information in a foolproof manner and the test subjects often diligently hunting for clues and hunches to circumvent the blinding. Recently, Mercury Pringting Inc., of New Brunswick, N.J., introduced a commercial double-blind label which relies upon a "scratch off" coating to blind certain information. These labels have been provided as perforated sheet stock. They are suitable for manual application to containers but can not be used in automated labeling machines that commonly use roll stock or individual labels. These labels also have the disadvantage that when they are applied to a container they provide their record of use as an extended tear-off tab which interferes with close-packed storage of the containers.
A properly designed label for a double-blind study will accomplish several critical objectives:
1. The label will display all information vital to the investigators and, in the case of drugs, comply with FDA regulations for the labeling of drugs.
2. To qualify for blind study use with drugs, label copy must include the drug's identity without revealing this information to any unauthorized group of people.
3. A portion of the label must remain permanently on the primary drug container. Ideally, the label should also have a portion which the investigator can remove and place in the test subject's records or in other records of the test.
It is an object of the present invention to provide a label which meets the requirements of blind studies and which can be applied to containers with conventional automatic labeling equipment. It is a further object of this invention to provide labeled containers which are suited for double-blind studies.